Stereoscopic display device and method

ABSTRACT

In a one-dimensional IP (vertical disparity discarding system), it is made possible to obtain a perspective projection image with no distortion or reduced distortion. A stereoscopic display device is provided with a display device including a display plane in which pixels are arranged flatly in a matrix shape; and a parallax barrier including a plurality of apertures or a plurality of lenses and being configured to control directions of rays from the pixels such that a horizontal disparity is included but a vertical disparity is not included. A horizontal direction pitch of the parallax barrier is integer times a horizontal pitch of the pixels, the display plane of the display device is divided so as to correspond to elemental images for respective apertures or the lenses of the parallax barrier, and an image whose vertical direction corresponds to a perspective projection in a fixed viewing distance and whose horizontal direction corresponds to an orthographic projection is divided and arranged for respective columns of the pixels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This a divisional of application Ser. No. 11/797,933, filed May 9, 2007,which is a divisional of Ser. No. 10/809,512, filed Mar. 26, 2004, nowU.S. Pat. No. 7,281,802 which claims priority of Japanese PatentApplication No. 2003-90738, filed Mar. 28, 2003, all of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stereoscopic display device and astereoscopic display method.

2. Related Art

As a stereoscopic video image display device which allows display of amotion picture, a so-called three-dimensional display, ones of varioussystems have been known. In recent years, particularly, a display deviceof a flat panel type employing a system where dedicated eyeglasses orthe like are not required is demanded highly. As a stereoscopic motionpicture display device of such a type, there is known one using aprinciple of holography, which is difficult to be put in a practicaluse. A system where a beam controlling element is installed in front ofa display panel (a display device) whose pixel positions are fixed, suchas a liquid crystal display device, a plasma display device of a directview type or a projection type is known as a system which can berealized relatively easily.

The beam controlling element is generally called a parallax barrier, andit has a structure that different images can be seen according to anangle change even at one or the same position. Specifically, in case ofonly a left and right disparity (a horizontal disparity), a slit or alenticular sheet (or a lenticular plate) is used, and in case that an upand down disparity (a vertical disparity) is included, a pin hole or alens array is used. The systems using the parallax barrier also areclassified to a binocular system, a multiview system, an super multiviewsystem (an super multiview condition of a multiview system) and anintegral photography (hereinafter, abbreviated as IP). A basic principlecommon to these types is the same as that used in a stereoscopicphotograph invented about a hundred years ago.

In a simplest binocular system, a certain viewpoint is defined, and adisplay panel and a parallax barrier are arranged such that differentimages are respectively seen at the right eye and the left eye of aviewer at the position of the defined viewpoint. A projection plane isprovided on the beam controlling element at a distance from theviewpoint to the beam controlling element, and two perspectiveprojection images having projection centers at the right eye and lefteye positions are divided vertically for each pixel column and therespective divided pieces are arranged alternately in the display panel.Realization can be achieved relatively easily. In the binocular system,however, there are severe drawbacks that an image is not viewedstereoscopically at positions except for a defined position and aviewing zone is very narrow, that an image appears as a reversedstereoscopic view (pseudoscopy), namely, an abnormal image such that adepth are viewed in a reversed manner when the image is seen at aposition moved by a interpupilliary distance (IPD) in left and rightdirections. There is an advantage that switching between atwo-dimensional display and a three-dimensional display can also beperformed easily, but application of the binocular system is only aneasy application such as a small-sized display.

In order to broaden the narrow viewing zone substantially, a methodwhere the pseudoscopy of the binocular type is avoided by a viewpointtracking or a head tracking technique has been proposed. As examples ofthe method, there are a method which switches left and right parallaximages from each other, and a method which moves a lenticular sheet infront and rear directions and in left and right directions. Further, amethod where an indicator for confirming whether or not an image is outof the viewing zone is provided separately below a screen or around ithas been known. In the case of the binocular system, the indicator canallow detection of front and rear and left and right directions. As anexample of a viewpoint tracking technique for expanding an effectiveviewing zone, there has been known an example where an image is changedwith a fixed viewpoint according to change in elevation angle of ascreen, or an example where a screen angle is tracked (a screen isrotated on a horizontal axis) at a time of viewpoint movement and animage is also changed. There is also an example where the parallaxbarrier system is not employed but adjustment of a disappearing point ofa transparent image, a view line detection/a perspective transformation,and an zooming-in/out are conducted.

In the multiview system, the number of parallax is increased from fourto about eight so that the number of positions where an image appearsnormally is increased. In case that a viewer moves laterally to changehis/her viewing angle, he/she sees different images depending on anangle from a stereoscopic display (motion parallax). However, an imagewhich is not continuous but “flipping” appears after a blackout where anangle changes quickly. Further, in the multiview system, the problemabout the pseudoscopy still remains.

The super multiview system is constituted such that a parallax image isdivided very finely independent of IPD and beams comprising a pluralityof parallax images enter in the pupil of a viewer. Thereby, the flippingis cancelled and a more natural image can be obtained. However, since anamount of image information to be processed increases by leaps andbounds as compared with the multiview system, which results indifficulty in realization.

In the multiview system or the super multiview system, there occurs acase of including not only a horizontal disparity but also a verticaldisparity. In such a system, however, since the amount of imageinformation to be processed increases by leaps and bounds, it isdifficult to realization the system.

The integral photography system (IP system) may be called “integralvideography system (IV system)”, “integral imaging system (II system)”or the like, but it is a system which utilizes a lens (a fly's eye lens)similar to a compound eye of an insect as a parallax barrier to arrangeelemental images corresponding to respective lenses behind the lensesand perform displaying, where a completely continuous motion parallaxcan be achieved without including the flipping and beams approximatingto a real material in a horizontal direction/in a vertical direction/inan oblique direction can be reproduced. This system is an ideal systemwhich allows a normal stereoscopic view even if a viewer turns his/herface sidelong or obliquely. It is desirable that the elemental imagecomprises continuous pixels which are not discrete pixels of finitesize. However, even if the elemental image is constituted with acollection of discrete pixels such as liquid crystal display panels, acontinuous motion parallax with a level which causes no problempractically can be obtained by using pixels with a high fineness of apixel pitch.

In the IP system which also includes a vertical disparity, namely, atwo-dimensional IP system, however, since the amount of imageinformation to be processed increases by leaps and bounds it isdifficult to realize such a system. On the other hand, in aone-dimensional IP system which is the IP system where the verticaldisparity has been cancelled, since a continuous motion parallax in ahorizontal direction can be obtained, a stereoscopic view with a highdisplay quality can be achieved as compared with the binocular system orthe multiview system, and the amount of image information to beprocessed can be reduced as compared with the super multiview system.

The IP system has a viewing zone in front and rear directions boarderthan the multiview system, but the one-dimensional IP system has aviewing zone in front and rear direction narrower than thetwo-dimensional IP system. Since there is no vertical disparity in theone-dimensional IP system, a perspective projection image is displayedon the assumption of a certain viewing distance in a vertical direction.Accordingly, an image is distorted except for a determined viewingdistance (in a range including the distance to some extent in front andrear directions) and a correct three-dimensional image can not beobtained. As a result, it is not recognized that there is a largedifference between the one-dimensional IP system and the multiviewsystem in a viewing zone in front and rear direction.

The multiview system is the same as the one-dimensional IP system in apoint that there is no parallax in a vertical direction. However, theviewing zone in front and rear directions is originally narrow in themultiview system, which does not constrain the viewing zone. In casethat the number of parallaxes is as many as about sixteen in themultiview system, the region in the front and rear directions which isout of viewing distance in the multiview system is substantially thesame as the one-dimensional IP system, though an image is distorted.That is, this means that a special version of the one-dimensional IPsystem is the multiview system. In the two-dimensional IP system, sincea three-dimensional image of a correct perspective projection is seen ina vertical direction and in a lateral direction according to a viewingdistance, no distortion occurs, which results in that thetwo-dimensional IP system has a viewing zone in the front and reardirections broader than the one-dimensional IP system or the multiviewsystem.

The one-dimensional IP system where the elemental image is constitutedwith discrete pixels includes the multiview system by definition. Thatis, of the one-dimensional IP systems, such a special case that theelemental image comprises pixels of a relatively small number of integerpixel columns, a lens accuracy is high (namely, the m-th specific pixelof n parallaxes can securely be seen from any aperture), and aconverging (condensing) interval of light beams (crossing lines betweena plane connecting the pixel column and a viewing distance plane) isequal to an IPD (62 mm to 65 mm) is the multiview system. Here, aposition of a viewpoint (a single-eye) is fixed to a reference position,and a difference in column number between a pixel viewed from anaperture just from the front and a pixel viewed from an apertureadjacent thereto is defined as a pixel column number per elemental image(which may be a fraction instead of an integer) (for example, refer toJ. Opt. Soc. Am. A vol. 15, p. 2059 (1998)). A pitch of the elementalimage is determined according to an interval between slit centersprojected from a viewpoint on to a pixel plane of display panel, but itis not determined from a pixel pitch itself on a display panel.

In the multiview system, pixel centers in a display panel must bepositioned on an extension line of both the eyes and all apertures (forexample, a slit), so that a high design precision is required. When theeye position is shifted leftward or rightward, it moves at a positionwhere a light shielding portion (a black matrix) between respectivepixels can be seen, and when the position is further shifted, anadjacent pixel can be seen (flipping).

On the other hand, in the one-dimensional IP system, a pixel on thedisplay panel can be seen or a black matrix can be seen, or differentpositions of each pixel can be seen on an extension line of both theeyes and each aperture. An aperture pitch and a pixel width have norelation each other (ideally, a display which has no pixel such as aphotograph assumed), and a very high design precision is not required.Even if the eye position is deviated, a ratio between pixels where anopening is seen and pixels where a black matrix is seen is not changedso that a flipping does not occur. In this connection, since theaperture pitch when seen from the eye position does not meet integertimes the pixel pitch, moire may be seen in case that a black matrix cannot be ignored particularly by using a slit.

The one-dimensional IP system which is handled in this specificationdoes not include the multiview system. The definition of theone-dimensional IP system except the multiview system lies in a pointthat the number of pixel columns in an elemental image is not integer(or a large number which can be assumed to be infinite, and fine), evenif there is a position where the pixel columns and a plane connectingapertures forms a crossing line to converge, the converging interval isnot equal to an IPD (62 mm to 65 mm) and is different from the viewingdistance. In the multiview system, the left and right eyes view adjacentpixel columns, and in the super multiview system, they view pixelcolumns which are not adjacent to each other. In the IP system, the eyesmay view pixel columns which may be adjacent to each other or not. Thisis because a continuous image where no pixel is within an elementalimage is originally supposed in the IP system. Even in either themultiview system or the IP system, when a pixel column group (elementalimage) cycle and a pupil (aperture of lens or slit) cycle are comparedwith each other in a correct design, the latter is shorter than theformer without any exception. Incidentally, in extreme conditionsunrelated with the practical use, such as a case that the viewingdistance is infinite, a case that a screen is infinitely small or thelike, the both are identical.

In case that the slit and the display panel are close to each other andthe viewing distance is relatively far, the both take valuesapproximating to each other. For example, in case that the viewingdistance is 1 m, the slit pitch is 0.7 mm, and a gap which is a distancebetween the slit and the pixel plane of the display panel is 1 mm, thepixel group cycle becomes 0.7007 mm, which is longer than the slit pitchby 0.1%. Assuming that the number of pixels in the lateral direction is640, the full width of the slit and the full width of the pixel displayportion are deviated from each other by 0.448 mm. Since the deviation isrelatively small, even if the pixel group cycle and the pupil cycle aredesigned to be equal to each other, an image is seen normally at aglance, in case that an image appears only around a central portion (forexample, both end portions have a solid color background), or in casethat, though a screen size is small, the viewing distance is long.However, the 3-D image can not be seen correctly up to both ends of thescreen.

As described above, even in either the multiview system or the IPsystem, when the elemental image cycle (pitch) and the aperture cycle(pitch) are compared with each other in a correct design, there is aslight difference between the both such as 0.1% or so, but the latter isshorter than the former without any exception. In some literatures ordocuments lacking in theoretical strictness, there is a description thatthe both are identical to each other, but these descriptions areerroneous. Further, there are some literatures which are thought todescribe that the both pitches are identical to each other in such ameaning as a case that an image has been seen by an eye (a perspectiveprojection centering the position of the eyes), namely, in such ameaning that, since the pupil is positioned on this side of theelemental image, actually different pitch is seen as the same pitch. Ingeneral, a difference between the IP system and the LS (lenticularsheet) system is considered to be a difference whether pixels exist onan image plane or they exist on a focal plane. However, in an actualdesign, and in particular in case that the number of pixels is numerous,a difference between the image plane and the focal plane is 0.1 mm orless, even if there is no aberration. Therefore, it is difficult todiscriminate between the image plane and the focal plane regarding theprecision and it is also difficult to make discrimination about whetherthere is presence or absence of convergence of beams in the viewingdistance. The IP system in this specification indicates such aconstitution that discrimination is not made on the basis of thepositions of the image plane and the focal plane and that a viewpointposition in a lateral direction where a normal stereoscopic image can beseen in the viewing distance is arbitrary (continuous). Further, themultiview system in the present specification is not equivalent to theLS system (irrespective of presence/absence of convergence of beams),and it indicates such a constitution that a viewpoint position in alateral direction where a normal stereoscopic image can be seen in theviewing distance is defined on the basis of an IPD.

Since the viewing distance is generally finite even in either the IPsystem or the multiview system, a display image should be produced suchthat a perspective projection image in the viewing distance can be seenactually. It is a usual method to produce a perspective projection imagefor each crossing point (crossing line) between a line (plane)connecting pixels (a pixel column) and a slit, and a viewing distanceplane. In the case of the multiview system, the number of crossing linesbetween the pixel column and the slit is converged to 16, if the numberof viewpoints in the multiview system is 16. Therefore, 16 perspectiveprojection images (all faces) must be produced.

In an ordinary IP system, since convergence of beams does not occur atthe viewing distance, perspective projection images (each may be onepixel column instead of all the faces) regarding all pixel column numbermust be produced. It is thought that, when a computation program iscreated skillfully, the amount of computation itself is not so difficultfrom that in the multiview system, but a procedure for creation of theprogram becomes very complicated. Incidentally, in a special caseincluded in the IP where the slit pitch becomes integer times (forexample, 16 times) the pixel pitch (even in this case, the pitch of theelemental image is longer than the slit pitch and it is not integertimes the pixel pitch), when a display image is produced by producing 16orthographic projection images and distributing them for respectivepixel columns, a perspective projection image can be seen in ahorizontal direction as actually viewed from a viewpoint.

However, an image appearing in this producing method results in aperspective projection in a horizontal direction and an orthographicprojection in a vertical direction. Here, a method where the perspectiveprojection is made on a fixed plane along lines converging to one point(a viewpoint, a projection center point) and the orthographic projectionis made on a fixed plane along parallel lines which do not converge isemployed. However, in the“horizontally-perspective/vertically-orthographic projection”,projection is made on a fixed plane along such lines as converging toone vertical line (which converge in a horizontal direction but does notconverge in a vertical direction). In the one-dimensional IP, since aperspective projection image corresponding to the viewing distance canbe obtained in the horizontal direction but a vertical disparity iscancelled, a perspective projection image must be displayed on theassumption of a certain viewing distance in the vertical direction.

Accordingly, when the vertical direction and the horizontal directionare combined, there occurs a problem that an image is distorted exceptfor a predetermined viewing distance. In the binocular system or themultiview system, when an image is out of the viewing zone in a front orrear direction, the image becomes a breakup image so that it does notappear to be stereoscopic. On the other hand, in the one-dimensional IP,there is a merit that a front and rear range where an image appears tobe stereoscopic is wide, but this merit can not be eventually utilizedsufficiently due to distortion occurrence. A precedent has not beenfound that the projection method or the front and rear viewing distancefor an original image in the one-dimensional IP was discussed strictly.

In this connection, in case that an image is photographed as an actualimage, which is different from a case that a projection image isproduced from a computer graphics, it becomes necessary tosimultaneously photograph the image by a camera with a multi-viewpointand perform such processings as an interpolation, an image conversion orthe like.

A method where a convex flexible display plane which is a multiviewsystem is provided, the display plane and a lens are positioned at thesame curvature center and the curvature center is set at a position ofthe head according to detection of the head is disclosed (refer to, forexample, JP06-289320A).

As described in detail, since there is not a vertical disparity in theone-dimensional IP system, there occurs a problem that a perspectiveprojection image in a vertical direction must be displayed on theassumption of a certain viewing distance and the image is distortedexcept for at the distance.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstancesand an object thereof is to provide a stereoscopic display device whichcan obtain a correct perspective projection image which has nodistortion or has a reduced distortion in one-dimensional IP system (avertical disparity discarding system).

A stereoscopic display device of a one-dimensional integral photographysystem according to a first aspect of the present invention includes: adisplay unit including a display plane in which pixels are arrangedflatly in a matrix shape; and a parallax barrier including a pluralityof apertures or a plurality of lenses and being configured to controldirections of rays from the pixels such that a horizontal disparity isincluded but a vertical disparity is not included, a horizontaldirection pitch of the parallax barrier being integer times a horizontalpitch of the pixels, the display plane of the display unit being dividedso as to correspond to elemental images for respective apertures or thelenses of the parallax barrier, and an image subjected to a perspectiveprojection in a fixed viewing distance in a vertical direction andsubjected to an orthographic projection in a horizontal direction beingdivided and arranged for respective columns of the pixels.

A stereoscopic display device of a one-dimensional integral photographysystem according to a second aspect of the present invention includes: adisplay unit including a display plane in which pixels are arrangedflatly in a matrix shape; a parallax barrier including a plurality ofapertures or a plurality of lenses and being configures to controldirections of rays from the pixels such that a horizontal disparity isincluded but a vertical disparity is not included; and a viewingdistance adjusting function which changes a vertical directionperspective projection image according to change in viewing distance,the display plane of the display unit being divided so as to correspondto elemental images for respective apertures or the lenses of theparallax barrier.

A stereoscopic display device of a one-dimensional integral photographysystem according to a third aspect of the present invention includes: adisplay unit including a display plane in which pixels are arrangedflatly in a matrix shape; a parallax barrier including a plurality ofapertures or a plurality of lenses and being configured to controldirections of rays from the pixels such that a horizontal disparity isincluded but a vertical disparity is not included; and a detectingmechanism configured to detect an out-of-viewing zone to the displayplane in up and down or front and rear directions, the display plane ofthe display unit being divided so as to correspond to elemental imagesfor respective apertures or the lenses of the parallax barrier.

A stereoscopic display device of a one-dimensional integral photographysystem according to a fourth aspect of the present invention includes: adisplay unit including a display plane in which pixels are arrangedflatly in a matrix shape; and a parallax barrier including a pluralityof apertures or a plurality of lenses and being configured to controldirections of rays from the pixels such that a horizontal disparity isincluded but a vertical disparity is not included, the display plane ofthe display unit being divided so as to correspond to elemental imagesfor respective apertures or the lenses of the parallax barrier, and thedisplay plane of the display unit being formed in a shape of a curvedface in a vertical direction, and the a perspective projection image ina vertical direction where the center point determined from the radiusof curvature of the curved face is defined as a viewing distanceposition being displayed on the display plane.

A stereoscopic display method of a one-dimensional integral photographysystem according to a fifth aspect of the present invention includes:displaying pixels in a display plane which are arranged flatly in amatrix shape; and controlling directions of rays from the pixels suchthat a horizontal disparity is included but a vertical disparity is notincluded by a parallax barrier including a plurality of apertures or aplurality of lenses; a horizontal direction pitch of the parallaxbarrier being integer times a horizontal pitch of the pixels, thedisplay plane of the display unit being divided so as to correspond toelemental images for respective apertures or the lenses of the parallaxbarrier, and an image subjected to a perspective projection in a fixedviewing distance in a vertical direction and subjected to anorthographic projection in a horizontal direction being divided andarranged for respective columns of the pixels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 are views illustrating an image arranging method of astereoscopic display device according to a first embodiment of thepresent invention, FIG. 1( a) being a front view of a liquid crystaldisplay panel and a parallax barrier according to the first embodiment,FIG. 1( b) being a plan view illustrating an image arrangement accordingto the first embodiment and FIG. 1( c) being a side view illustratingthe image arrangement of the stereoscopic device according to the firstembodiment;

FIG. 2 is a flowchart showing a display image producing procedureaccording to the first embodiment;

FIG. 3 is a table showing assignment to pixels in a orthographicprojection direction used as a lookup table in the display imageproducing procedure illustrated in FIG. 2 or FIG. 19;

FIG. 4 is a view illustrating the stereoscopic display device used inthe first embodiment of the present invention;

FIG. 5 is a table showing comparison with another system;

FIG. 6 is a view illustrating a viewing zone in an integral photographysystem;

FIG. 7A is a view illustrating a viewing zone of a binocular system;

FIG. 7B is a view illustrating a viewing zone of a multiview system;

FIG. 8A is a view illustrating a frame of a cube displayed by thestereoscopic display device of the first embodiment;

FIG. 8B is a frame of a cube displayed by a stereoscopic display deviceof a comparative example;

FIG. 9 is a graph showing a relationship between a distortion factor ofa stereoscopic image and a viewing distance;

FIG. 10 is a diagram showing a positional relationship among pixels, anelemental image and a parallax barrier in a binocular system or amultiview system;

FIG. 11 is a diagram showing a positional relationship among pixels, anelemental image and a parallax barrier in an integral photographysystem;

FIG. 12 is a diagram showing a positional relationship among pixels, anelemental image and a parallax barrier in an integral photography systemaccording to the first embodiment of the present invention;

FIG. 13 is a view illustrating an out-of-viewing zone alarming functionof an indicator of a stereoscopic display device according to a thirdembodiment of the present invention;

FIG. 14A is a plan view of a stereoscopic display device according to amodified embodiment of the third embodiment of the present invention;

FIG. 14B is a front view illustrating an out-of-viewing zone alarmingfunction according to a blind structure of the stereoscopic displaydevice according to the modified embodiment of the third embodiment;

FIG. 15A is a plan view illustrating the stereoscopic display deviceaccording to another modified embodiment of the third embodiment of thepresent invention;

FIG. 15B is a front view illustrating an out-of-viewing zone alarmingfunction according to a blind structure of the stereoscopic displaydevice according to the another modified embodiment of the thirdembodiment;

FIG. 16 is a view illustrating a stereoscopic display device providedwith a display face curved in a vertical direction according to anothermodified embodiment of a fourth embodiment of the present invention;

FIG. 17 is a diagram illustrating an image projection method and animage arrangement method of the stereoscopic display device according tothe first embodiment of the present invention;

FIG. 18 is a diagram illustrating an image arrangement method of thestereoscopic display device according to the first embodiment of thepresent invention;

FIG. 19 is a flowchart showing a display image producing procedureaccording to the second embodiment;

FIG. 20 is a flowchart showing a display image producing procedureaccording to a comparative example 1;

FIG. 21A to FIG. 21D are photographs showing a projection view producedaccording to a projection method according to an embodiment of thepresent invention and projection views produced according to otherprojection methods;

FIG. 22 is views showing projection views produced by setting acomputation column range as the minimum according to the embodiment ofthe present invention; and

FIG. 23 is a graph showing the computation column range according to theembodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be explained in detail belowwith reference to the drawings. These embodiments are described for easyunderstanding of the present invention. The embodiments may be modifiedvariously within the scope or spirit of the present invention and thepresent invention is not limited to these embodiments.

First Embodiment

A stereoscopic display device according to the first embodiment of thepresent invention will be explained with reference to FIG. 1 to FIG. 12.The stereoscopic display device according to this embodiment is providedwith a liquid crystal panel 31 serving as a flat display device and aparallax barrier 32, as illustrated in FIG. 1 and FIG. 4. FIG. 1( a) isa front view of the liquid crystal panel 31 and the parallax barrier 32,FIG. 1( b) is a plan view illustrating an image arrangement of astereoscopic display device according to the embodiment, and FIG. 1( c)is a side view illustrating the image arrangement of the stereoscopicdisplay device according to the embodiment. FIG. 4 is a transmissionview illustrating the image arrangement of the stereoscopic displaydevice according to the embodiment.

As far as the display device 31 is constituted such that pixels whosepositions are defined within a display plane are arranged flatly in amatrix manner, it may be any one of a liquid crystal display device of adirect view type or a projection type, a plasma display device, adisplay device of a field emission, an organic EL display device and thelike. In this embodiment, the display device used is of the direct viewtype where a diagonal size is 20.8 inches, the number of pixels is 3,200in a horizontal direction and 2,400 in a vertical direction, each pixelis divided lengthwise into 3 sub-pixels of red, green and blue (RGB),and the pitch of the sub-pixel is 44 μm.

As the parallax barrier 32, a slit or a lenticular sheet (a cylindricallens array) 34 extending in a substantially vertical direction andhaving a cyclic structure in a substantially horizontal direction, asillustrated in FIG. 12, where a pitch (cycle) in a horizontal directionis 0.704 mm corresponding to 16 sub-pixels. In this connection, FIG. 12is a view illustrating a positional relationship among pixels, anelemental image and a parallax barrier in the integral photographysystem according to this embodiment. In FIG. 12, reference numeral 31denotes a liquid crystal panel, reference numeral 61 denotes anelemental image width (pitch), reference numeral 62 denotes a lenspitch, and reference numeral 63 denotes a number of a parallax image. Agap between a display plane (an inner plane between glass substrates) ofthe liquid crystal panel 31 which is the display device and the parallaxbarrier 32 is effectively set to about 2 mm considering refractiveindexes of the glass substrate or the lens material. That is, alenticular sheet with a thickness of about 3.1 mm corresponds to a gapof 2 mm in a case of a slit having the same parallax image arrangement,because a beam (principal ray) direction is refracted outside and insidethe lens.

One where not a pitch appearing due to a difference in a distance in theeye of a viewer but an actual pitch of the parallax barrier 32 isinteger times the pixel pitch is not a multiview but a one-dimensionalintegral photography, as described above. The arrangement illustrated inFIG. 12 is not classified to a multiview, because in this arrangement aviewing distance where beams converge to approach to 17 view system isabout 32 mm, which is impossible practically, and a converging intervalis not equal to an IPD, and beams do not converge in any other viewingdistances. The one-dimensional integral photography, as illustrated inFIG. 4, shows disparity only in a horizontal direction 41, and an imagechanges according to a viewing distance, but it does not show disparityin a vertical direction 42 and a fixed image can be obtained regardlessof the viewing distance. In this connection, reference numeral 73 inFIG. 4 denotes a viewing distance sensor (an observer position detector)used in the second embodiment described later.

In FIG. 1, when a viewing distance plane is defined as a flat face 43 aor a flat face 43 b, a pitch 61 a or a pitch 61 b of the elemental imageis determined according to an interval of aperture centers projected ona pixel plane on the display panel 31 from viewpoints on the visualdistance plane 43 a or the 43 b as described above. Reference numerals46 a and 46 b denote lines connecting the viewpoint position and theaperture centers, which do not pass through the centers of pixels in theone-dimensional IP necessarily, as illustrated in FIG. 11 and FIG. 12.On the other hand, the connecting lines pass through the centers ofpixels 35 in the multiview system, as illustrated in FIG. 10, and theline 46 connecting the viewpoint position 43 and the aperture center iscoincident with a beam. Incidentally, FIG. 10 is a view illustrating apositional relationship among pixels, an elemental image and a parallaxbarrier (the slit 33) of a binocular or a multiview system.

In this embodiment, since a horizontal pitch of the aperture is integertimes the pixel, a pitch 61 of the elemental image becomes a numberdeviated from the integer times of the pixel 35, as illustrated in FIG.12. In this connection, even if a horizontal pitch 62 of the aperture isnot integer times the pixel, the pitch 61 of the elemental imagegenerally becomes a number deviated from the pixel in theone-dimensional integral photography, which is illustrated in FIG. 11.FIG. 11 is a view illustrating a positional relationship among pixels,an elemental image and a parallax barrier (the slit 33) in the integralphotography system. On the other hand, in the multiview system, thepitch 61 of the elemental image is integer times a pixel as illustratedin FIG. 10.

A display image producing procedure of the stereoscopic display deviceaccording to the embodiment is illustrated in FIG. 2. In case of acomputer graphics, there is provided object data (polygon), and in caseof a actually shot images, a plurality of shot images from differentangles (a crossing type multi-viewpoint camera) or different positions(a parallel type multi-viewpoint camera) is converted to object data.The converting method has been described, for example, in Final Reportof “Advanced 3-D Tele-Vision Project” by the TelecommunicationAdvancement Organization (TAO) of Japan issued September, 2002 (Section2.8 and the like). Vertically-perspective and horizontally-orthographicprojection images are produced by the number of parallaxes. In case of aviewing distance of 1 m, all 9,600 columns are collectively computed inorthographic projections in 36 directions.

A grouping of pixels in specific 36 directions is shown in a centercolumn (in case of viewing distance L=1000 mm) in FIG. 3. FIG. 3 is atable illustrating assignment to pixels in an orthographic projectiondirection, which is used as a lookup table in the display imageproducing procedure. Incidentally, in FIG. 3, the left side column showsa case that the viewing distance L is 500 mm and the right side columnshows a case that the viewing distance L is 1500 mm. Since the number oforthographic projection directions and a computation range aredetermined by determining the viewing distance, such a fact can be madein a lookup table in advance. An orthographic projection image isproduced by rendering and texture mapping according to such a method asa ray-tracing and it is divided and arranged in respective columns for36 directions to be composed, so that a display image is completed.

The procedure illustrated in FIG. 2 will be explained specifically belowwith reference to FIG. 17. An object (subject) 21 to be displayed isprojected on a projection plane 22 which is positioned at the sameposition as the display plane to be actually displayed in the plane oflenticular plate by the liquid crystal panel to form an image 24. Atthis time, the object is projected along projection lines 25 extendingtoward a projection-center line 23 which is parallel to the projectionplane 22 at a front face (the center in a vertical direction) and ispositioned within a viewing distance plane such that a verticaldirection corresponds to a perspective projection and a horizontaldirection corresponds to an orthographic projection. The projectionlines 25 do not cross one another in a horizontal direction but theycross one another in a vertical direction at the projection-center line23. The vertically-perspective and horizontally-orthographic projectionimage 24 of the subject is produced on the projection plane by theprojection method.

This method is the same as a rendering operation in a commerciallyavailable three-dimensional computer graphics producing software exceptthat there is a difference in projection process between a verticaldirection and a horizontal direction. In the three-dimensional computergraphics producing software, if such a camera that a perspectiveprojection is performed in a vertical direction and an orthographicprojection is performed in a horizontal direction is defined, thisprojection method can be performed easily. Specifically, a cameracombined such that a horizontal direction (x-axis) takes an output formof an orthographic projection camera and a vertical direction (y-axis)takes an output form of a perspective projection can be defined. Animage (parallax image) 26 corresponding to one direction where aperspective projection and a orthographic projection have beenrespectively performed in a vertical direction and a horizontaldirection on the projection plane 22 is divided for each one pixelcolumn in a vertical direction and these divided pixel columns arearranged on the pixel plane 27 of the display device at intervals ofaperture pitch Ws (at intervals of pixel columns comprising a fixednumber of pixels). The above operation is repeated regarding the otherprojection directions 28 so that the entirety of the pixel plane 27 iscompleted. As the projection directions 28, only 8 directions of −4, −3,−2, −1, 1, 2, 3, 4 are illustrated in FIG. 17, but several tensdirections will be required according to the viewing distance. Eachprojection direction corresponds to a parallax number, but respectivedirections are set such that they do not have equal angles but formequal intervals on the viewing distance plane (the projection-centerline). That is, parallel translation (orientation is fixed) of a camerais performed on the projection-center line at equal intervals. Each ofthe projected images 26 may be produced with only columns positioned ina required range, and the required range is shown in a table in FIG. 3.

Four kinds of examples of the projection method are illustrated in FIG.21A to FIG. 21D. FIG. 21A illustrates an orthographic projection, FIG.21B illustrates a perspective projection, FIG. 21C illustrates avertically-perspective and horizontally-orthographic projection, andFIG. 21D illustrates a vertically-orthographic andhorizontally-perspective projection. Each parallax image in thisembodiment is obtained by the projection method illustrated in FIG. 21C,and FIG. 22 illustrates an example of images projected in the total 36directions with a viewing distance of 1 m. Since images are not producedexcept for a required range, an unnecessary range becomes black.

FIG. 18 illustrates an image arrangement in a pixel plane of the displaydevice. The pixel plane of the display device is divided into elementalimages corresponding to respective apertures. Each of the elementalimages in this embodiment is constituted with 16 or 17 pixel columns 65(the elemental image width 61 is originally a number between 16 times or17 times the pixel width, but it is set to 16 times or 17 timesaccording to the position in order to make assignment digitally). Thenumber of the pixel columns which allows assignment of a parallax is9,600 columns (3,200×RGB), the number of apertures is 600 (the range ofthe aperture number 64 is −300 to −1 and 1 to 300), and the aperturepitch Ws is equal to the width of the pixel column of 16. In respectivepixel columns 65, corresponding parallax image numbers 63 (in thisexample, corresponding to 36 directions of −18 to −1 and 1 to 18) areillustrated.

In FIG. 3, aperture numbers where arrangement of a parallax image in them-th direction is started and stopped are shown. For example, in case ofthe viewing distance of 1 m, the −18^(th) parallax image is arrangedbetween an aperture number with a number of −299 (since an aperturenumber with a number of −300 and aperture numbers subsequent thereto areout of a pixel area of the display device, they are removed) and that of−297, which is illustrated in FIG. 18. That is, in the case of theviewing distance of 1 m, a parallax image with a number of −18 can beobtained by producing three columns of pixels. The elemental image withan aperture number of 1 comprises pixel columns of 16 parallaxes withparallax numbers of −8 to −1 and 1 to 8, and the elemental image with anaperture number of −299 comprises pixel columns of 16 parallaxes withparallax numbers of −18 to −3. Of course, pixel columns divided withineach elemental image are arranged in the order of the parallax number.The same parallax number appears for each 16 pixel columns without anyexception. Since the elemental image width 61 is slightly larger thanthe width of 16 pixel columns, a boundary of the elemental image isrequired to match with the nearest pixel column boundary (an ordinaryA-D conversion), therefore the pixel column number to an aperture is 16columns in most of apertures, but 17 columns to an aperture also appear.A parallax number range in an aperture is shifted one by one on theaperture number comprising 17 columns. The aperture numbers comprising17 columns are the numbers of apertures positioned at both ends defininga range where an image with each parallax number is arranged, and 17columns are defined by apertures with numbers of 16, 47, 79, 110, 141,172, 204, 235, 266 and 297 (and their minus numbers) appearing in Startand Stop columns of Table illustrated in FIG. 3 (in case of a viewingdistance of 1 m).

As described above, a horizontally-orthographic andvertically-perspective projection image which have been producedcollectively for each direction within only a required range are dividedand arranged for each pixel column so that a display image on thedisplay device is produced.

As a first comparative example, an ordinary one-dimensional IP systemwhere a horizontal pitch of an aperture is not integer times ahorizontal pitch of a pixel is considered. A stereoscopic display deviceof the first comparative example takes an image display procedureillustrated in FIG. 20. In this case, since horizontal viewpoints aredifferent for respective columns, a perspective projection image in adifferent direction for each column must be produced. If the number ofpixels is the same number as this embodiment, it is necessary to compute9,600 directions individually, which results in complication incomputation procedure.

As a second comparative example, an ordinary one-dimensional IP systemwhere a horizontal pitch of an aperture is integer times a horizontalpitch of a pixel but images are produced by orthographic projectionsboth in a vertical direction and in a horizontal direction. In thiscase, an image can be produced easily without necessity for determininga viewing distance, and a stereoscopic image can be made possible inbroad front and rear directions according to the kind or the content ofan image. However, there is a problem of distortion of the imageactually produced.

FIG. 8A and FIG. 8B are views which have displayed frames of a cube,FIG. 8A illustrating a frame of a cube displayed by the stereoscopicdisplay device of this embodiment and FIG. 8B illustrating a frame ofthe cube displayed by the second comparative example. In the secondcomparative example, as illustrated in FIG. 8B, it will be understoodthat a face 51 b on this side of the cube is spread laterally and a face52 b on the depth side thereof is narrowed laterally, so that the cubedoes not appear to be square and distorts largely though it is seen fromits front. In this embodiment, as illustrated in FIG. 8A, a face 51 a onthis side of the cube and a face 52 a on the depth side are displayedwithout any distortion, and even if the viewing distance moves slightlyforward or rearward, a distortion is small. Distortion factors in thepresent embodiment and the second comparative example are shown in FIG.9. As understood from FIG. 9, a distortion in a viewing distance of 1 mis 10% or more in the second comparative example, but the distortion ina viewing distance of about 1 m is suppressed to 5% or less in thisembodiment.

As a third comparative example, FIG. 7A illustrates a viewing zone of abinocular system and FIG. 7B illustrates a viewing zone of aneight-viewpoint system. Positions of both the eyes which allow a normalstereoscopic view are indicated by reference numeral 48. A viewing zone47 is limited to a region indicated by a dark area and it becomes apseudoscopic view at a position indicated by reference numeral 49. Inthis embodiment, as illustrated in FIG. 6, an image which hardlyincludes distortion is displayed continuously (without causing apseudoscopic view) in left and right directions at a front or rearposition in a range 44 within a stereoscopic view enabling range 45which does not include a breakup image. A distortion slightly occurs ina range 45 except for the range 44 but a stereoscopic view is allowed.Incidentally, FIG. 6 is a view illustrating a viewing zone in theintegral photography system. Further, in FIG. 6, FIG. 7A and FIG. 7B,reference numeral 46 denotes a line or plane crossing a viewpoint and anaperture center (which is not limited to a case that the line or planepasses through the center of a pixel), and reference numeral 61 denotesa width (pitch) of an elemental image.

The above-described results will be collectively shown in FIG. 5. Asunderstood from FIG. 5, the stereoscopic display device of theembodiment can obtain an excellent advantage, as compared with thebinocular or multiview system, or the ordinary one-dimensional IPsystem.

As explained above, according to the embodiment, a distortion can bereduced and a viewing zone in front or rear direction can besubstantially spread even in a one-dimensional IP system, andcomputation method can be facilitated.

Second Embodiment

Next, a second embodiment of the present invention will be explainedwith reference to FIG. 1 to FIG. 19. A stereoscopic display device ofthe embodiment is constituted by further adding a function for inputtinga viewing distance and displaying an image corresponding to the inputviewing distance to the stereoscopic display device of the firstembodiment. Inputting means for the viewing distance may be such amanual inputting device as a button, a knob, a software switch or thelike, and it may be constituted so as to dispose the viewing distancesensor (the observer position detector) 73 on the liquid crystal panel31 to perform automatic detection and conduct feedback of the detecteddata to an image to be displayed, for example, as illustrated in FIG. 4.As the viewing distance sensor 73, for example, an autofocus measuringelement used in a camera can be utilized.

In this connection, besides the detection of the position of theobserver, the position of a mouse can be detected in a personalcomputer, and the position of a remote controller may be detected in aTV set.

In this embodiment, for example, when the viewing distance is changeddue to transfer from the viewing distance plane 43 a to the viewingdistance plane 43 b in FIG. 1, such a change can be responded byperforming switching from the elemental image width 61 a to theelemental image width 61 b. In the procedure illustrated in FIG. 19,when the vertically-perspective and horizontally-orthographic projectionimages are produced by the number corresponding to the number ofparallaxes, the horizontal direction viewpoint is always fixed, so thatimages can be collectively computed in 54 directions which do not changedue to the viewing distance, as shown in FIG. 3. FIG. 23 illustrates thecomputation range in FIG. 3 in a graphic form. If a total range ofparallelograms to correspond to respective viewing distances is alwaysset as the computation range, it becomes unnecessary to change thecomputation range due to change in viewing distance.

On the other hand, in case that change in viewing distance isaccommodated in the first comparative example to the first embodiment,it is necessary to compute 9,600 directions changed due to change inviewing distance individually, which results in increase in computationamount.

In this embodiment, a range 44 with a small distortion in FIG. 6 movesforward or rearward according to the viewing distance, so that a statewhich hardly includes distortion is always maintained. In thisconnection, in FIG. 6, reference numeral 45 denotes a stereoscopic viewenabling range which does not include a breakup image, reference numeral46 denotes a line or a plane connecting a viewpoint and an aperture(which does not pass through the pixel center necessarily), andreference numeral 61 denotes an elemental image width (pitch).

A stereoscopic image of perspective projection with no distortion orwith reduced distortion is always displayed by changing the elementalimage width according to change in viewing distance and simultaneouslychanging a perspective projection image in a vertical direction. Imageswith different viewing distances are prepared in advance, or they areproduced by real-time computation.

Such a constitution can be employed that the elemental image width ischanged according to change in viewing distance and simultaneously animage is enlarged/reduced. In this case, since re-computation where aviewing distance of the perspective projection has been changed is notrequired, such a constitution is convenient on the processing. However,there is a drawback that a stereoscopic object appears to have the samesize even if the viewing distance is changed.

Alternatively, such a constitution can be employed that the elementalimage width is changed by performing stepwise switching among fixedviewing distances without performing continuous adjustment according tochange in viewing distance. For example, switching among three steps ofviewing distances of 500 mm, 1,000 mm and 1,500 mm illustrated in FIG. 3is performed. In this case, such a constitution can be adopted that theelemental image widths are switched according to change in viewingdistance and simultaneously the image is enlarged/reduced.Alternatively, such a constitution can be employed that perspectiveprojection images with different viewing distances only in a verticaldirection are changed according to a viewing distance change within afixed range where the elemental image widths are not switched.

A general method of perspective transformation has been described, forexample, in “THREE-DIMENSIONAL DISPLAY” (written by Chihiro MASUDA;published by SANGYO TOSHO, 1990) (refer to Chapter 4). In thisembodiment, the perspective transformation is performed only in ahorizontal direction. As an advantage, an image which does not include abreakup image or a distortion can be obtained in any viewing distance,and this embodiment is specifically effective for application where anydistortion is not allowed, such as a medical application, a designapplication or the like.

Third Embodiment

A third embodiment of the present invention will be explained withreference to FIG. 13 to FIG. 15. A stereoscopic display device of thisembodiment is constituted by providing a vertical direction indicator 72which can detect that a viewpoint 43 of an observer is positioned out ofa viewing zone in up and down directions and in front and reardirections in a stereoscopic display device of a one-dimensionalintegral photography system, as illustrated in FIG. 13. That is, thestereoscopic display device of the embodiment is provided with analarming function which detects such a fact that the viewpoint 43 of theobserver is positioned out of the viewing zone in up and down directionsand in front and rear directions and outputs alarm. Incidentally, FIG.13 is a view illustrating a constitution of the stereoscopic displaydevice provided with the vertical direction indicator according to theembodiment. In this connection, in FIG. 13, reference numeral 41 denotesa horizontal viewing angle and reference numeral 42 denotes a verticalviewing angle.

Further, an out-of-viewing zone alarming function 71 having such a blindstructure as illustrated in FIGS. 14A, 14B, 15A and 15B may be provided.In FIGS. 14A and 15A, reference numeral 42 denotes a vertical directionviewing angle, reference numeral 43 a denotes a viewing distance plane,reference numeral 43 c denotes a viewing distance plane out of a normalviewing distance with no distortion (or with reduced distortion), andreference numeral 44 denotes a normal viewing distance with nodistortion (or with reduced distortion). Incidentally, FIG. 14A is aside view of a stereoscopic display device provided with anout-of-viewing zone alarming function 71 having a blind structure, andFIG. 14B is a front view of the out-of-viewing zone alarming function 71having the blind structure. FIG. 15A is a side view of a stereoscopicdisplay device provided with another out-of-viewing zone alarmingfunction 71 having a blind structure, and FIG. 15B is a front view ofthe out-of-viewing zone alarming function 71 having the blind structure.In this connection, in FIGS. 15A and 15B, the out-of-viewing zonealarming function 71 is formed in a concave curved shape to an observer.

As illustrated in FIG. 14B and FIG. 15B, both the vertical directionindicator 72 and the blind structure 71 have a cyclic structure in avertical direction. The indicator 72 is designed such that itsindication appears with different colors or brightnesses or differentmessages are respectively displayed in a normal viewing zone and out ofthe range. In the case, for example, the indicator 72 may be constitutedby overlapping two sheets of forming patterns in front and rear. Theblind structure 71 is formed along a direction of perspective projectionradially only in a vertical direction. There is a case that the blindstructure having the curved shape illustrated in FIG. 15A is easier inmanufacture than the blind structure illustrated in FIG. 14A. Thereby,an advantage that alarming is given or an image disappears when theimage is distorted can be obtained easily, and this embodiment isspecifically effective for application where any distortion is notallowed, such as a medical application, a design application or thelike.

In this connection, the out-of-viewing zone alarming function explainedin the third embodiment may be provided in the first embodiment.

Fourth Embodiment

A fourth embodiment of the invention will be explained with reference toFIG. 16. A stereoscopic display device of this embodiment is constitutedsuch that a display plane of a display unit 31 including a parallaxbarrier 32 is curved in a vertical direction, and a stereoscopic imageof perspective projection is displayed by displaying a verticaldirection perspective projection image, where the center pointdetermined from the radius of curvature is defined as a viewing distanceposition 43 a. In this connection, in FIG. 16, reference numeral 42denotes a vertical direction viewing angle and reference numeral 44denotes a normal viewing distance with no distortion (or with reduceddistortion).

In this embodiment, further, a curvature changing mechanism 81 whichchanges the curvature of the display plane may be provided.Incidentally, when the viewing distance varies, distortion can not becorrected by only changing the curvature. In such a case, therefore, itis necessary to provide a display image adjustment similar to the onedescribed in the second embodiment. The display device 31 with a curveface can be made by grinding a glass plate of an assembled liquidcrystal display device to make it thinner.

As explained above, according to this embodiment, a perspectiveprojection image with reduced distortion can be obtained.

This embodiment is effective as assistant means for suppressingdistortion in case of a large screen.

Though the present invention has been explained through the respectiveembodiments with reference to the drawings, the present invention is notlimited to these embodiments. The present invention can be implementedin variously modified modes within the scope and spirit of theinvention.

As described above, according to the embodiments of the presentinvention, a perspective projection image with reduced distortion can beobtained.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcepts as defined by the appended claims and their equivalents.

1. A stereoscopic display device of a one-dimensional integralphotography system, comprising: a display unit including a display planein which pixels are arranged flatly in a matrix shape; a parallaxbarrier including a plurality of apertures or a plurality of lenses andbeing configured to control directions of rays from the pixels such thata horizontal disparity is included but a vertical disparity is notincluded; and a detecting mechanism which detects an out-of-viewing zoneto the display plane in up and down or front and rear directions, thedetecting mechanism having a blind structure, the blind structure havinga cyclic structure in a vertical direction; a horizontal direction pitchof the parallax barrier being integer times a horizontal pitch of thepixels, the display plane of the display unit being divided so as tocorrespond to elemental images for respective apertures or the lenses ofthe parallax barrier, and an image subjected to a perspective projectionin a fixed viewing distance in a vertical direction and subjected to anorthographic projection in a horizontal direction being divided andarranged for respective columns of the pixels.
 2. A stereoscopic displaymethod of a one-dimensional integral photography system, comprising:displaying pixels in a display plane which are arranged flatly in amatrix shape; controlling directions of rays from the pixels such that ahorizontal disparity is included but a vertical disparity is notincluded by a parallax barrier including a plurality of apertures or aplurality of lenses; and detecting an out-of-viewing zone to the displayplane in up and down or front and rear directions by a verticaldirection indicator having a cyclic structure in a vertical direction, ahorizontal direction pitch of the parallax barrier being integer times ahorizontal pitch of the pixels, the display plane of the display unitbeing divided so as to correspond to elemental images for respectiveapertures or the lenses of the parallax barrier, and an image subjectedto a perspective projection in a fixed viewing distance in a verticaldirection and subjected to an orthographic projection in a horizontaldirection being divided and arranged for respective columns of thepixels.
 3. A stereoscopic display method of a one-dimensional integralphotography system, comprising: displaying pixels in a display planewhich are arranged flatly in a matrix shape; controlling directions ofrays from the pixels such that a horizontal disparity is included but avertical disparity is not included by a parallax barrier including aplurality of apertures or a plurality of lenses; and detecting anout-of-viewing zone to the display plane in up and down or front andrear directions by a detecting mechanism having a blind structure, ahorizontal direction pitch of the parallax barrier being integer times ahorizontal pitch of the pixels, the display plane of the display unitbeing divided so as to correspond to elemental images for respectiveapertures or the lenses of the parallax barrier, and an image subjectedto a perspective projection in a fixed viewing distance in a verticaldirection and subjected to an orthographic projection in a horizontaldirection being divided and arranged for respective columns of thepixels.
 4. A stereoscopic display method of a one-dimensional integralphotography system, comprising: displaying pixels in a display planewhich are arranged flatly in a matrix shape; controlling directions ofrays from the pixels such that a horizontal disparity is included but avertical disparity is not included by a parallax barrier including aplurality of apertures or a plurality of lenses; and detecting anout-of-viewing zone to the display plane in up and down or front andrear directions by a detecting mechanism having a blind structure havinga curved shape, a horizontal direction pitch of the parallax barrierbeing integer times a horizontal pitch of the pixels, the display planeof the display unit being divided so as to correspond to elementalimages for respective apertures or the lenses of the parallax barrier,and an image subjected to a perspective projection in a fixed viewingdistance in a vertical direction and subjected to an orthographicprojection in a horizontal direction being divided and arranged forrespective columns of the pixels.